The US Department of Agriculture proposed strict nutrition guidelines for school food yesterday — but the Big Apple has already put most of the healthy measures in place.

The proposals, which raise the standards for federally funded meals for the first time in 15 years, are a renewed effort to tackle childhood-obesity rates that have tripled in recent decades.

They include increasing the amount of fruits, vegetables and grains served while reducing the amount of sodium, calories and fat in school meals.

“We understand that these improved meal standards may present challenges for some school districts, but the new law provides important new resources, technical assistance and flexibility to help schools raise the bar for our kids,” said Agriculture Secretary Tom Vilsack.

The city has already eliminated white bread and whole milk from schools and in 2005 started baking french fries instead of frying them.